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Linux 3.4.102
[linux/fpc-iii.git] / drivers / virtio / virtio_mmio.c
blob01d6dc250d5c50a8c01ea22d34818721d8c845d5
1 /*
2 * Virtio memory mapped device driver
3 *
4 * Copyright 2011, ARM Ltd.
5 *
6 * This module allows virtio devices to be used over a virtual, memory mapped
7 * platform device.
8 *
9 * Registers layout (all 32-bit wide):
10 *
11 * offset d. name description
12 * ------ -- ---------------- -----------------
13 *
14 * 0x000 R MagicValue Magic value "virt"
15 * 0x004 R Version Device version (current max. 1)
16 * 0x008 R DeviceID Virtio device ID
17 * 0x00c R VendorID Virtio vendor ID
18 *
19 * 0x010 R HostFeatures Features supported by the host
20 * 0x014 W HostFeaturesSel Set of host features to access via HostFeatures
21 *
22 * 0x020 W GuestFeatures Features activated by the guest
23 * 0x024 W GuestFeaturesSel Set of activated features to set via GuestFeatures
24 * 0x028 W GuestPageSize Size of guest's memory page in bytes
25 *
26 * 0x030 W QueueSel Queue selector
27 * 0x034 R QueueNumMax Maximum size of the currently selected queue
28 * 0x038 W QueueNum Queue size for the currently selected queue
29 * 0x03c W QueueAlign Used Ring alignment for the current queue
30 * 0x040 RW QueuePFN PFN for the currently selected queue
31 *
32 * 0x050 W QueueNotify Queue notifier
33 * 0x060 R InterruptStatus Interrupt status register
34 * 0x060 W InterruptACK Interrupt acknowledge register
35 * 0x070 RW Status Device status register
36 *
37 * 0x100+ RW Device-specific configuration space
38 *
39 * Based on Virtio PCI driver by Anthony Liguori, copyright IBM Corp. 2007
40 *
41 * This work is licensed under the terms of the GNU GPL, version 2 or later.
42 * See the COPYING file in the top-level directory.
43 */
44
45 #include <linux/highmem.h>
46 #include <linux/interrupt.h>
47 #include <linux/io.h>
48 #include <linux/list.h>
49 #include <linux/module.h>
50 #include <linux/platform_device.h>
51 #include <linux/slab.h>
52 #include <linux/spinlock.h>
53 #include <linux/virtio.h>
54 #include <linux/virtio_config.h>
55 #include <linux/virtio_mmio.h>
56 #include <linux/virtio_ring.h>
57
58
59
60 /* The alignment to use between consumer and producer parts of vring.
61 * Currently hardcoded to the page size. */
62 #define VIRTIO_MMIO_VRING_ALIGN PAGE_SIZE
63
64
65
66 #define to_virtio_mmio_device(_plat_dev) \
67 container_of(_plat_dev, struct virtio_mmio_device, vdev)
68
69 struct virtio_mmio_device {
70 struct virtio_device vdev;
71 struct platform_device *pdev;
72
73 void __iomem *base;
74 unsigned long version;
75
76 /* a list of queues so we can dispatch IRQs */
77 spinlock_t lock;
78 struct list_head virtqueues;
79 };
80
81 struct virtio_mmio_vq_info {
82 /* the actual virtqueue */
83 struct virtqueue *vq;
84
85 /* the number of entries in the queue */
86 unsigned int num;
87
88 /* the index of the queue */
89 int queue_index;
90
91 /* the virtual address of the ring queue */
92 void *queue;
93
94 /* the list node for the virtqueues list */
95 struct list_head node;
96 };
97
98
99
100 /* Configuration interface */
101
102 static u32 vm_get_features(struct virtio_device *vdev)
103 {
104 struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vdev);
105
106 /* TODO: Features > 32 bits */
107 writel(0, vm_dev->base + VIRTIO_MMIO_HOST_FEATURES_SEL);
108
109 return readl(vm_dev->base + VIRTIO_MMIO_HOST_FEATURES);
110 }
111
112 static void vm_finalize_features(struct virtio_device *vdev)
113 {
114 struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vdev);
115 int i;
116
117 /* Give virtio_ring a chance to accept features. */
118 vring_transport_features(vdev);
119
120 for (i = 0; i < ARRAY_SIZE(vdev->features); i++) {
121 writel(i, vm_dev->base + VIRTIO_MMIO_GUEST_FEATURES_SEL);
122 writel(vdev->features[i],
123 vm_dev->base + VIRTIO_MMIO_GUEST_FEATURES);
124 }
125 }
126
127 static void vm_get(struct virtio_device *vdev, unsigned offset,
128 void *buf, unsigned len)
129 {
130 struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vdev);
131 u8 *ptr = buf;
132 int i;
133
134 for (i = 0; i < len; i++)
135 ptr[i] = readb(vm_dev->base + VIRTIO_MMIO_CONFIG + offset + i);
136 }
137
138 static void vm_set(struct virtio_device *vdev, unsigned offset,
139 const void *buf, unsigned len)
140 {
141 struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vdev);
142 const u8 *ptr = buf;
143 int i;
144
145 for (i = 0; i < len; i++)
146 writeb(ptr[i], vm_dev->base + VIRTIO_MMIO_CONFIG + offset + i);
147 }
148
149 static u8 vm_get_status(struct virtio_device *vdev)
150 {
151 struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vdev);
152
153 return readl(vm_dev->base + VIRTIO_MMIO_STATUS) & 0xff;
154 }
155
156 static void vm_set_status(struct virtio_device *vdev, u8 status)
157 {
158 struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vdev);
159
160 /* We should never be setting status to 0. */
161 BUG_ON(status == 0);
162
163 writel(status, vm_dev->base + VIRTIO_MMIO_STATUS);
164 }
165
166 static void vm_reset(struct virtio_device *vdev)
167 {
168 struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vdev);
169
170 /* 0 status means a reset. */
171 writel(0, vm_dev->base + VIRTIO_MMIO_STATUS);
172 }
173
174
175
176 /* Transport interface */
177
178 /* the notify function used when creating a virt queue */
179 static void vm_notify(struct virtqueue *vq)
180 {
181 struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vq->vdev);
182 struct virtio_mmio_vq_info *info = vq->priv;
183
184 /* We write the queue's selector into the notification register to
185 * signal the other end */
186 writel(info->queue_index, vm_dev->base + VIRTIO_MMIO_QUEUE_NOTIFY);
187 }
188
189 /* Notify all virtqueues on an interrupt. */
190 static irqreturn_t vm_interrupt(int irq, void *opaque)
191 {
192 struct virtio_mmio_device *vm_dev = opaque;
193 struct virtio_mmio_vq_info *info;
194 struct virtio_driver *vdrv = container_of(vm_dev->vdev.dev.driver,
195 struct virtio_driver, driver);
196 unsigned long status;
197 unsigned long flags;
198 irqreturn_t ret = IRQ_NONE;
199
200 /* Read and acknowledge interrupts */
201 status = readl(vm_dev->base + VIRTIO_MMIO_INTERRUPT_STATUS);
202 writel(status, vm_dev->base + VIRTIO_MMIO_INTERRUPT_ACK);
203
204 if (unlikely(status & VIRTIO_MMIO_INT_CONFIG)
205 && vdrv && vdrv->config_changed) {
206 vdrv->config_changed(&vm_dev->vdev);
207 ret = IRQ_HANDLED;
208 }
209
210 if (likely(status & VIRTIO_MMIO_INT_VRING)) {
211 spin_lock_irqsave(&vm_dev->lock, flags);
212 list_for_each_entry(info, &vm_dev->virtqueues, node)
213 ret |= vring_interrupt(irq, info->vq);
214 spin_unlock_irqrestore(&vm_dev->lock, flags);
215 }
216
217 return ret;
218 }
219
220
221
222 static void vm_del_vq(struct virtqueue *vq)
223 {
224 struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vq->vdev);
225 struct virtio_mmio_vq_info *info = vq->priv;
226 unsigned long flags, size;
227
228 spin_lock_irqsave(&vm_dev->lock, flags);
229 list_del(&info->node);
230 spin_unlock_irqrestore(&vm_dev->lock, flags);
231
232 vring_del_virtqueue(vq);
233
234 /* Select and deactivate the queue */
235 writel(info->queue_index, vm_dev->base + VIRTIO_MMIO_QUEUE_SEL);
236 writel(0, vm_dev->base + VIRTIO_MMIO_QUEUE_PFN);
237
238 size = PAGE_ALIGN(vring_size(info->num, VIRTIO_MMIO_VRING_ALIGN));
239 free_pages_exact(info->queue, size);
240 kfree(info);
241 }
242
243 static void vm_del_vqs(struct virtio_device *vdev)
244 {
245 struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vdev);
246 struct virtqueue *vq, *n;
247
248 list_for_each_entry_safe(vq, n, &vdev->vqs, list)
249 vm_del_vq(vq);
250
251 free_irq(platform_get_irq(vm_dev->pdev, 0), vm_dev);
252 }
253
254
255
256 static struct virtqueue *vm_setup_vq(struct virtio_device *vdev, unsigned index,
257 void (*callback)(struct virtqueue *vq),
258 const char *name)
259 {
260 struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vdev);
261 struct virtio_mmio_vq_info *info;
262 struct virtqueue *vq;
263 unsigned long flags, size;
264 int err;
265
266 /* Select the queue we're interested in */
267 writel(index, vm_dev->base + VIRTIO_MMIO_QUEUE_SEL);
268
269 /* Queue shouldn't already be set up. */
270 if (readl(vm_dev->base + VIRTIO_MMIO_QUEUE_PFN)) {
271 err = -ENOENT;
272 goto error_available;
273 }
274
275 /* Allocate and fill out our active queue description */
276 info = kmalloc(sizeof(*info), GFP_KERNEL);
277 if (!info) {
278 err = -ENOMEM;
279 goto error_kmalloc;
280 }
281 info->queue_index = index;
282
283 /* Allocate pages for the queue - start with a queue as big as
284 * possible (limited by maximum size allowed by device), drop down
285 * to a minimal size, just big enough to fit descriptor table
286 * and two rings (which makes it "alignment_size * 2")
287 */
288 info->num = readl(vm_dev->base + VIRTIO_MMIO_QUEUE_NUM_MAX);
289 while (1) {
290 size = PAGE_ALIGN(vring_size(info->num,
291 VIRTIO_MMIO_VRING_ALIGN));
292 /* Already smallest possible allocation? */
293 if (size <= VIRTIO_MMIO_VRING_ALIGN * 2) {
294 err = -ENOMEM;
295 goto error_alloc_pages;
296 }
297
298 info->queue = alloc_pages_exact(size, GFP_KERNEL | __GFP_ZERO);
299 if (info->queue)
300 break;
301
302 info->num /= 2;
303 }
304
305 /* Activate the queue */
306 writel(info->num, vm_dev->base + VIRTIO_MMIO_QUEUE_NUM);
307 writel(VIRTIO_MMIO_VRING_ALIGN,
308 vm_dev->base + VIRTIO_MMIO_QUEUE_ALIGN);
309 writel(virt_to_phys(info->queue) >> PAGE_SHIFT,
310 vm_dev->base + VIRTIO_MMIO_QUEUE_PFN);
311
312 /* Create the vring */
313 vq = vring_new_virtqueue(info->num, VIRTIO_MMIO_VRING_ALIGN, vdev,
314 true, info->queue, vm_notify, callback, name);
315 if (!vq) {
316 err = -ENOMEM;
317 goto error_new_virtqueue;
318 }
319
320 vq->priv = info;
321 info->vq = vq;
322
323 spin_lock_irqsave(&vm_dev->lock, flags);
324 list_add(&info->node, &vm_dev->virtqueues);
325 spin_unlock_irqrestore(&vm_dev->lock, flags);
326
327 return vq;
328
329 error_new_virtqueue:
330 writel(0, vm_dev->base + VIRTIO_MMIO_QUEUE_PFN);
331 free_pages_exact(info->queue, size);
332 error_alloc_pages:
333 kfree(info);
334 error_kmalloc:
335 error_available:
336 return ERR_PTR(err);
337 }
338
339 static int vm_find_vqs(struct virtio_device *vdev, unsigned nvqs,
340 struct virtqueue *vqs[],
341 vq_callback_t *callbacks[],
342 const char *names[])
343 {
344 struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vdev);
345 unsigned int irq = platform_get_irq(vm_dev->pdev, 0);
346 int i, err;
347
348 err = request_irq(irq, vm_interrupt, IRQF_SHARED,
349 dev_name(&vdev->dev), vm_dev);
350 if (err)
351 return err;
352
353 for (i = 0; i < nvqs; ++i) {
354 vqs[i] = vm_setup_vq(vdev, i, callbacks[i], names[i]);
355 if (IS_ERR(vqs[i])) {
356 vm_del_vqs(vdev);
357 return PTR_ERR(vqs[i]);
358 }
359 }
360
361 return 0;
362 }
363
364 static const char *vm_bus_name(struct virtio_device *vdev)
365 {
366 struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vdev);
367
368 return vm_dev->pdev->name;
369 }
370
371 static struct virtio_config_ops virtio_mmio_config_ops = {
372 .get = vm_get,
373 .set = vm_set,
374 .get_status = vm_get_status,
375 .set_status = vm_set_status,
376 .reset = vm_reset,
377 .find_vqs = vm_find_vqs,
378 .del_vqs = vm_del_vqs,
379 .get_features = vm_get_features,
380 .finalize_features = vm_finalize_features,
381 .bus_name = vm_bus_name,
382 };
383
384
385
386 /* Platform device */
387
388 static int __devinit virtio_mmio_probe(struct platform_device *pdev)
389 {
390 struct virtio_mmio_device *vm_dev;
391 struct resource *mem;
392 unsigned long magic;
393
394 mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
395 if (!mem)
396 return -EINVAL;
397
398 if (!devm_request_mem_region(&pdev->dev, mem->start,
399 resource_size(mem), pdev->name))
400 return -EBUSY;
401
402 vm_dev = devm_kzalloc(&pdev->dev, sizeof(*vm_dev), GFP_KERNEL);
403 if (!vm_dev)
404 return -ENOMEM;
405
406 vm_dev->vdev.dev.parent = &pdev->dev;
407 vm_dev->vdev.config = &virtio_mmio_config_ops;
408 vm_dev->pdev = pdev;
409 INIT_LIST_HEAD(&vm_dev->virtqueues);
410 spin_lock_init(&vm_dev->lock);
411
412 vm_dev->base = devm_ioremap(&pdev->dev, mem->start, resource_size(mem));
413 if (vm_dev->base == NULL)
414 return -EFAULT;
415
416 /* Check magic value */
417 magic = readl(vm_dev->base + VIRTIO_MMIO_MAGIC_VALUE);
418 if (memcmp(&magic, "virt", 4) != 0) {
419 dev_warn(&pdev->dev, "Wrong magic value 0x%08lx!\n", magic);
420 return -ENODEV;
421 }
422
423 /* Check device version */
424 vm_dev->version = readl(vm_dev->base + VIRTIO_MMIO_VERSION);
425 if (vm_dev->version != 1) {
426 dev_err(&pdev->dev, "Version %ld not supported!\n",
427 vm_dev->version);
428 return -ENXIO;
429 }
430
431 vm_dev->vdev.id.device = readl(vm_dev->base + VIRTIO_MMIO_DEVICE_ID);
432 vm_dev->vdev.id.vendor = readl(vm_dev->base + VIRTIO_MMIO_VENDOR_ID);
433
434 writel(PAGE_SIZE, vm_dev->base + VIRTIO_MMIO_GUEST_PAGE_SIZE);
435
436 platform_set_drvdata(pdev, vm_dev);
437
438 return register_virtio_device(&vm_dev->vdev);
439 }
440
441 static int __devexit virtio_mmio_remove(struct platform_device *pdev)
442 {
443 struct virtio_mmio_device *vm_dev = platform_get_drvdata(pdev);
444
445 unregister_virtio_device(&vm_dev->vdev);
446
447 return 0;
448 }
449
450
451
452 /* Platform driver */
453
454 static struct of_device_id virtio_mmio_match[] = {
455 { .compatible = "virtio,mmio", },
456 {},
457 };
458 MODULE_DEVICE_TABLE(of, virtio_mmio_match);
459
460 static struct platform_driver virtio_mmio_driver = {
461 .probe = virtio_mmio_probe,
462 .remove = __devexit_p(virtio_mmio_remove),
463 .driver = {
464 .name = "virtio-mmio",
465 .owner = THIS_MODULE,
466 .of_match_table = virtio_mmio_match,
467 },
468 };
469
470 static int __init virtio_mmio_init(void)
471 {
472 return platform_driver_register(&virtio_mmio_driver);
473 }
474
475 static void __exit virtio_mmio_exit(void)
476 {
477 platform_driver_unregister(&virtio_mmio_driver);
478 }
479
480 module_init(virtio_mmio_init);
481 module_exit(virtio_mmio_exit);
482
483 MODULE_AUTHOR("Pawel Moll <pawel.moll@arm.com>");
484 MODULE_DESCRIPTION("Platform bus driver for memory mapped virtio devices");
485 MODULE_LICENSE("GPL");
Linux with added FPC-III support